Effect of bacterial peptidoglycan on erythrocyte death and adhesion to endothelial cells

Peptidoglycans, bacterial wall components, have previously been shown to trigger eryptosis, the suicidal erythrocyte death, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine exposure at the cell surface. Phosphatidylserine exposing erythrocytes adhere to the vascular wall at least partially by interaction of erythrocytic phosphatidylserine with endothelial CXC chemokine ligand 16 (CXCL16). The present study explored whether peptidoglycan exposure fosters the adhesion of erythrocytes to human umbilical vein endothelial cells (HUVEC). To this end, HUVEC were treated for 48 h with peptidoglycan (10 μg/ml) and CXCL16 abundance determined by confocal microscopy and FACS analysis. Moreover, human erythrocytes were exposed for 48 h to peptidoglycan (10 μg/ml) and phosphatidylserine exposure estimated from binding of fluorescent annexin-V, cell volume from forward scatter in FACS analysis and erythrocyte adhesion to human umbilical vein endothelial cells (HUVEC) from trapping of labeled erythrocytes in a flow chamber. As a result, bacterial peptidoglycan exposure was followed by increased CXCL16 expression in HUVEC as well as erythrocyte shrinkage, phosphatidylserine exposure and adhesion to HUVEC under flow conditions at arterial shear rates. The adhesion was significantly attenuated but not abrogated in the presence of either, erythrocyte phosphatidylserine-coating annexin-V (5 μl/ml) or CXCL16 neutralizing antibody directed against endothelial CXCL16 (4 μg/ml). In conclusion, exposure to peptidoglycan increases endothelial CXCL16 expression and leads to eryptosis followed by phosphatidylserine- and CXCL16-mediated adhesion of eryptotic erythrocytes to vascular endothelial cells.     

渗透压、细胞容积与鼻咽癌细胞增殖

目的:研究渗透压、细胞容积与鼻咽癌细胞增殖的关系。方法:用MTT法检测在不同渗透压培养条件下低分化鼻咽癌细胞(CNE－2Z)的增殖能力,流式细胞仪测定细胞周期分布,活细胞图像分析测量细胞容积,台盼蓝拒染法检测细胞存活率。结果:高渗(370、440mOsmol/L)培养增大细胞容积和促进细胞增殖,细胞容积分别增大8.7%、27.8%,增殖率分别提高22.2%和33.9%;而低渗(160、230mOsmol/L)培养减小细胞容积和抑制增殖,细胞容积分别减小12.8%和4.1%,增殖率分别降低34.0%和15.6%;细胞容积与细胞增殖率呈正相关。非等渗长期培养条件下,细胞周期各时相分布没有显著差异。低渗培养降低细胞生存率。结论:胞外渗透压、细胞容积与鼻咽癌细胞增殖密切相关,低渗培养可能通过减小细胞容积、促进细胞死亡而抑制细胞增殖。     

Training induced effects on blood volume,erythrocyte turnover and haemoglobin oxygen binding properties

Summary The effect of three weeks ergometer training (Tr) 5 times a week for 45 min at 70% by 6 subjects on erythrocyte turnover and haemoglobin O₂ affinity has been studied. Increased reticulocytosis could be observed from the second day after beginning Tr until a few days after its end, probably caused by increased erythropoietin release by the kidney. Erythrocyte destruction was most pronounced in the first and markedly reduced in the third week of Tr. Elevated glutamate oxalacetate transaminase activity and creatine as well as lowered mean corpuscular haemoglobin indicate a younger erythrocyte population in the first week of recovery. Total blood volume increased during the course of Tr by 700 ml, mainly caused by a raised plasma volume (74%). Red cell volume increased later with maximal values one week after Tr (+280 ml). In this week the standard oxygen dissociation curve was most shifted to the right (P₅₀ increased from 3.77±0.05 kPa to 3.99±0.07 kPa) and the Bohr coefficients had their lowest values. Both effects are completely explainable by the haemoglobin O₂ binding properties of young erythrocytes.After training, all parameters of physical performance ( , maximal workload, heart rate during rest and exercise) were markedly improved, indicating fast adaptation mechanisms. The increased erythrocyte turnover, including higher erythropoiesis, seems to be one important part of these effects.A preliminary report was presented at the National Congress of Sports Medicine in Cologne, 1982. Furthermore, the content of this paper was part of the doctoral thesis of the first author     

Studies on the mechanisms of mucous cell depletion in experimental colitis

Mucous cell depletion is an important histological discriminator in favour of ulcerative colitis. The mechanism of this change was investigated in guinea pigs with experimental colitis induced by intrarectal instillation of acetic acid or dinitrochlorobenzene (DNCB) in sensitized animals. Both models showed mucous cell depletion. Increased numbers of mucous cells were flash-labelled with tritiated thymidine (3HTdR), indicating an increased pool of proliferating (oligo-) mucous cells; mucous cell production was in fact increased absolutely compared with control animals, and there was a marked increase in the rate of turnover of mucous cells. The results indicate that in colitis there is (i) increased mucous cell production and (ii) an increased rate of mucous cell turnover due to increased loss of older mucous cells. It is concluded that the disease process in experimental colitis leads to premature discharge of mucin, so that mucous cells are no longer recognizable by light microscopy. This explains the increase in mucin production in ulcerative colitis, which occurs even in the presence of significant mucous cell depletion.     

The molecular mechanism in activation-induced cell death of an Ag-reactive B cell clone

TPA-1 is a subclone of B cell hybridomas established by somatic hybridization using B cells of A/J mice immunized with TNP-LPS, and expresses a receptor for TNP on the cell membrane. The present study showed that TPA-1 was induced to apoptotic cell death upon treatment with TNP-BSA. Therefore, TPA-1 is considered to provide a good model for the study on activation-induced cell death of mature B cells induced by soluble antigen. TNP-BSA treatment caused the generation of a large amount of intracellular reactive oxygen species (ROS) of TPA-1, and the addition of the monovalent thiol-reactive compound: monochlorobimane (MCB) rescued it from apoptosis as well as the antioxidant reagent: N-acetyl-L-cysteine. Furthermore, MCB markedly inhibited the generation of ROS and prevented the disruption of mitochondrial membrane potential that was induced by TNP-BSA treatment. In addition, it counteracted the effect of TNP-BSA on the expression of the Bcl-2 family, resulting in down-regulation of Bax and Bad and up-regulation of Bcl-XL. Taken together, these results suggest strongly that oxidative stress of mitochondria may be involved directly in apoptotic cell death by engagement of antigen receptors on mature B cells with soluble antigen.     

Whither Autoimmunity: The Lessons of Anti-CCP and B cell Depletion

The most difficult component to understand in autoimmune disease has been the issue of causation. In contrast, there have been enormous gains in improved diagnostics as well as improved therapy. Indeed, the use of biologics have changed the profile of numerous autoimmune diseases. In this issue, we discuss two such aspects. Firstly, we place in perspective the use of anti-citrullinated protein antibodies in rheumatoid arthritis. Second, we discuss the increasing use of B cell depletion in the treatment of autoimmunity. Clinical Reviews in Allergy and Immunology is a unique venue for these themes because it covers the spectrum of allergy through autoimmunity. Indeed, we also present a special paper on the relationships of the hepatitis B virus and autoimmunity. Although the Th1 to Th2 dichotomy is well known to both murine and human immunologists, it is really in the study of specific inflammatory responses that they are correctly placed in the perspective of the continuum of immunopathology.     

肾透明细胞癌中AnnexinⅡ的表达及其临床意义

目的:探讨AnnexinⅡ在人肾透明细胞癌和癌旁组织样本中的表达情况及其临床意义。方法:采用Western blot方法检测29例新鲜肾透明细胞癌及相应癌旁组织中AnnexinⅡ蛋白的表达;采用免疫组织化学方法检测120例肾透明细胞癌及相应癌旁组织中AnnexinⅡ的表达情况,并将结果与患者的临床病理参数及预后进行相关性分析。结果:AnnexinⅡ在肾透明细胞癌及相应癌旁组织中均有表达,前者的表达水平较后者显著升高(P<0.01);免疫组织化学显示肾透明细胞癌组织中,AnnexinⅡ的阳性表达率高达67.5%,与癌旁组织存在明显差异(P<0.01);AnnexinⅡ在肾透明细胞癌组织中以胞膜表达为主,其表达状况与肾透明细胞癌患者的临床分期(P<0.05),组织学分级(P<0.05),肾被膜受侵(P<0.01)和远地转移(P<0.01)紧密相关;并且AnnexinⅡ的表达状况与肾透明细胞癌患者的5年生存率显著相关。结论:AnnexinⅡ在肾透明细胞癌组织中过表达,其与肾癌的发展密切相关,在肾癌的侵袭及转移过程中可能发挥重要作用。     

Expression of programmed cell death 1/programmed cell death ligand 1 in the tumor microenvironments of primary gastrointestinal diffuse large B cell lymphomas

Background

Gastrointestinal diffuse large B cell lymphoma (GI DLBCL) is the most common gastrointestinal lymphoma. However, there has not been a comprehensive investigation into the expression patterns of programmed cell death 1 (PD-1) and programmed cell death ligand 1(PD-L1) in GI DLBCL tissues.

Regulation and interplay of apoptotic and non-apoptotic cell death

Various death triggers including DNA damage, oxidative stress, and growth factor deprivation promote the loss of mitochondrial membrane potential, leading to the production of reactive oxidative species (ROS) or enhanced permeability of the mitochondrial membrane, otherwise known as mitochondrial membrane permeabilization, by insertion of Bax/Bak into the outer membrane where it interacts with voltage-dependent anion channel (VDAC)/adenine nucleotide transporter (ANT). MMP leads to the release of small pro-apoptotic molecules, which induce caspase-dependent and -independent apoptotic cell death. The production of ROS due to the loss of mitochondrial membrane potential enhances the permeability of lysosomal membranes, resulting in the release of lysosomal proteases, which contribute to mitochondrial membrane permeabilization and the lysosomal degradation mechanism of autophagic cell death. Although defects in apoptotic and non-apoptotic cell death pathways can be carcinogenic, these pathways are more or less preserved within cancer cells and can therefore influence cell death and mediate resistance to cancer treatment. This paper discusses recent advances in determining the molecular mechanisms behind regulation of apoptotic and non-apoptotic cell death, as well as the interplay between these two processes, which may lead to the development of new strategies by which to enhance the therapeutic effects of chemotherapeutic agents.     

RIPK3 in cell death and inflammation: the good,the bad,and the ugly

Necroptosis is a form of cell death that can be observed downstream of death receptor or pattern recognition receptor signaling under certain cellular contexts, or in response to some viral and bacterial infections. The receptor interacting protein kinases-1 (RIPK1) and RIPK3 are at the core of necroptotic signaling, among other proteins. Because this pathway is normally halted by the pro-apoptotic protease caspase-8 and the IAP ubiquitin ligases, how and when necroptosis is triggered in physiological settings are ongoing questions. Interestingly, accumulating evidence suggests that RIPK3 has functions beyond the induction of necroptotic cell death, especially in the areas of tissue injury and sterile inflammation. Here, we will discuss the role of RIPK3 in a variety of physiological conditions, including necroptotic and non-necroptotic cell death, in the context of viral and bacterial infections, tissue damage, and inflammation.     

Characterization of the osmotic-stress response inSaccharomyces cerevisiae: osmotic stress and glucose repression regulate glycerol-3-phosphate dehydrogenase independently

Micro-organisms have developed systems to adapt to sudden changes in the environment. Here we describe the response of the yeastSaccharomyces cerevisiae to osmotic stress. A drop in the water activity (a_w) of the medium following the addition of NaCl led to an immediate shrinkage of the cells. During the 2 h following the osmotic shock the cells partially restored their cell volume. This process depended on active protein synthesis. During the recovery period the cells accumulated glycerol intracellularly as a compatible solute and very little glycerol was leaking out of the cell. We have investigated in more detail the enzymes of glycerol metabolism and found that only the cytoplasmic glycerol-3-phosphate dehydrogenase was strongly induced. The level of induction was dependent on the yeast strain used and the degree of osmotic stress. The synthesis of cytoplasmic glycerol-3-phosphate dehydrogenase is also regulated by glucose repression. Using mutants defective in glucose repression (hxk2), or derepression (snf1), and with invertase as a marker enzyme, we show that glucose repression and the osmotic-stress response system regulate glycerol-3-phosphate dehydrogenase synthesis independently. We infer that specific control mechanisms sense the osmotic situation of the cell and induce responses such as the production and retention of glycerol.     

Homeostatic mass control in gastric non-neoplastic epithelia under infection of Helicobacter pylori: an immunohistochemical analysis of cell growth, stem cells and programmed cell death

We evaluated homeostatic mass control in non-neoplastic gastric epithelia under Helicobacter pylori (HP) infection in the macroscopically normal-appearing mucosa resected from the stomach with gastric cancer, immunohistochemically analyzing the proliferation, kinetics of stem cells and programmed cell death occurring in them. Ki67 antigen-positive proliferating cells were found dominantly in the elongated neck portion, sparsely in the fundic areas and sporadically in the stroma with chronic infiltrates. CD117 could monitor the kinetics of gastric stem cells and showed its expression in two stages of gastric epithelial differentiation, namely, in transient cells from the gastric epithelial stem cells to the foveolar and glandular cells in the neck portion and in what are apparently progenitor cells from the gastric stem cells in the stroma among the infiltrates. Most of the nuclei were positive for ssDNA in the almost normal mucosa, suggesting DNA damage. Cleaved caspase-3-positive foveolar cells were noted under the surface, suggesting the suppression of apoptosis in the surface foveolar cells. Besides such apoptosis of the foveolar cells, in the severely inflamed mucosa apoptotic cells were found in the neck portion where most of the cells were Ki67 antigen-positive proliferating cells. Beclin-1 was recognized in the cytoplasm and in a few nuclei of the fundic glandular cells, suggesting their autophagic cell death and mutated beclin-1 in the nuclei. Taken together, the direct and indirect effects of HP infection on the gastric epithelial proliferation, differentiation and programmed cell death suggested the in-situ occurrence of gastric cancer under HP infection.     

Role of mesangial cell contraction in adaptation of the glomerular tuft to changes in extracellular volume

Different chronic states of mesangial cell contraction were induced by variation of extracellular volume in Munich-Wistar rats for 6 days to study the influence of mesangial cells on the geometry of the glomerular tuft. Stereological analysis of superficial glomeruli in volume-expanded rats (VR, treated with enalapril) and volume-reduced rats (VR, treated with indomethacin) revealed a glomerular tuft volume 28.7% smaller, and a capillary luminal volume 32% smaller in VR than in VE rats. The filtration area [defined as glomerular basement membrane (GBM) area facing fenestrated endothelium] was greatly reduced in VR rats (97±16×10³ μm² vs 137±13×10³ μm²). The surface density (S_v) of the GBM was higher by approximately 10% in VR rats primarily due to the considerable increase in S_v of the perimesangial GBM subdivision (0.189±0.01 μm²/μm³ vs 0.153±0.01 μm²/μm³), indicating a higher degree of mesangial cell contraction in these animals. Our results suggest (1) that mesangial cell contraction plays a major role in the adaptation of the glomerular tuft to variations in extracellular volume; (2) that the relevance of mesangial cell contraction for the regulation of glomerular haemodynamics appears to be small; and (3) that the reduction in filtration area, although prominent, cannot fully account for the considerable decreases in the ultrafiltration coefficient observed by others in acute and chronic studies.     

The role of apoptotic volume decrease and ionic homeostasis in the activation and repression of apoptosis

The mechanism of activation and repression of apoptosis has been a central focus of many studies examining the role of programmed cell death in both normal and pathological conditions. Despite intensive research efforts, the precise cellular and molecular mechanisms that trigger and/or prevent apoptosis remain undefined. A universal characteristic of apoptosis is the loss of cell volume or cell shrinkage, recently termed apoptotic volume decrease. While cell shrinkage has traditionally been viewed as a passive event during apoptosis, recent work from several laboratories has shown that the loss of cell volume, or more specifically the flux of ions associated with the change in cell size, play a critical role in the regulation of the cell death machinery. On going studies continue to support the hypothesis that the change in intracellular ions can alter a cells decision to die by apoptosis.     

Necroptosis,pyroptosis and apoptosis: an intricate game of cell death

Cell death is a fundamental physiological process in all living organisms. Its roles extend from embryonic development, organ maintenance, and aging to the coordination of immune responses and autoimmunity. In recent years, our understanding of the mechanisms orchestrating cellular death and its consequences on immunity and homeostasis has increased substantially. Different modalities of what has become known as ‘programmed cell death’ have been described, and some key players in these processes have been identified. We have learned more about the intricacies that fine tune the activity of common players and ultimately shape the different types of cell death. These studies have highlighted the complex mechanisms tipping the balance between different cell fates. Here, we summarize the latest discoveries in the three most well understood modalities of cell death, namely, apoptosis, necroptosis, and pyroptosis, highlighting common and unique pathways and their effect on the surrounding cells and the organism as a whole.     

中性粒细胞非凋亡性程序化细胞死亡的研究概况

中性粒细胞是机体固有免疫应答的主要效应细胞，也是机体内重要的炎症细胞。中性粒细胞除了凋亡和坏死外，还存在一种非凋亡性程序化细胞死亡形式。该形式具有空泡化，线粒体通透性增大等形态学特征，具有caspase-3、caspase-8非依赖性以及无DNA片段化的生物化学特征。目前尚不知其确切的生物学意义，但它与发育和许多生理／病理现象有关。这些研究成果对于重新认识和定位中性粒细胞程丰化细胞死亡的多样性和复杂性提出了新的思路。     

Prostaglandin E2, collagenase,and cell death responses depend on cyclical load magnitude in an explant model of tendinopathy

Tendinopathy is a significant clinical problem that can result from repetitive activity. While the precise etiology of this condition remains unclear, the cellular response to cyclical loading is believed to have a contributory role to the pathology of tendinopathy. This study examined the short-term biochemical response of avian flexor digitorum profundus tendon to repetitive cyclic loadings of varying magnitude. An in vitro tendon explant model was utilized to apply four levels of haversine tensile stress (peak stress of 0, 3, 12, and 18 MPa) at 1.0 Hz, 8 hr/day for 3 days. The 12 and 18 MPa levels were known to cause significant mechanical damage based on previous work. Tissue media was recovered and analyzed for prostaglandin E₂ (PGE₂), lactate dehydrogenase (LDH, measure of cell death), and collagenase levels. Tissue samples were recovered and analyzed for cell viability, total collagen, and sulfated glycosaminoglycan content. Collagenase, LDH, and PGE₂ levels were found to be influenced by loading magnitude (p < 0.05) with higher levels being present at higher load magnitudes. Varying cyclical load magnitude caused minimal compositional changes as collagen content and glycosaminoglycan did not change. These results indicate that elevated cyclical mechanical loading of tendon quickly results in altered biochemical tissue responses indicative of tissue injury. More sustained cyclical loading over time may be required for these initial responses to induce more dramatic tissue changes as observed in clinical tendinopathy.     

Morphometric studies of the extraglomerular mesangial cell field in volume expanded and volume depleted rats

Summary The extraglomerular mesangial cell field was studied by morphometric techniques in volume expanded and volume depleted rats. The volume density of the extraglomerular mesangial interstitium was found to be significantly different between the two conditions, 16.9±3.7% in volume depletion and 29.0±4.1% in volume expansion. No difference in the volume density of the peritubular interstitium could be detected under the same conditions. These findings are interpreted as indicating a specific sensitivity of the extraglomerular mesangial interstitium to changes in body fluid content, a phenomenon which may play a role in the mechanism of resetting the tubulo-glomerular feedback control.